Cardiomyopathy treatment device with electrode therapy

ABSTRACT

This invention relates to implantable heart sack that can be equipped with pacemaker leads and/or defibrillation leads for the treatment of cardiomyopathy, hypertrophic cardiomyopathy tachycardia, bradycardia, ventricular fibrillation, atrial fibrillation etc. The hear sack was prepared from biocompatible, biostable, implantable polyetherurethane, polycarbonateurethane, silicone, polysiloxaneurethane, polyfluoroethylene, or hydrogenated poly(styrene-butadiene) copolymer. The heart sack is equipped with attached sutures to make it easier to attach onto the heart. The heart sack can be made semipermeable or perforated to have numerous holes. The heart sack can be reinforce with fiber or filament. Ordinary pacemaker leads can be attached to the inner side of the heart sack. However, the pacemaker leads of this invention were prepared from noble metal (gold, platinum, rhodium and platinum-Rhodium alloys) or stainless steel coated, deposited or plated mono-filaments, yarns, braids, cords, wires or films, or cylindrical tubes of polyamide, polyimide, polyester, and/or polypropylene that are encased in multi-lumen insulating tube or coaxial tube made of biocompatible, biostable, implantable polyetherurethane, polycarbonateurethane, silicone, polysiloxaneurethane, polyfluoroethylene, or hydrogenated poly(styrene-butadiene) copolymer. The leads can be mounted onto the inner surface of the heart sack and contoured to the heart. The heart sack can be coated with hydrophilic coating containing an antimicrobial agent that gives the heart sack a low coefficient of friction, excellent biocompatibility and antimicrobial properties.

FIELD OF THE INVENTION

This invention relates to a biocompatible, biostable and implantableheart sack which is prepared from biocompatible, biostable andimplantable elastomers selected from the group consisting ofpolyetherurethane, polycarbonateurethane, silicone, poly(siloxane)urethane and/or hydrogenated poly (styrene-butadiene) copolymer for thetreatment of cardiomyopathy, hypertrophic cardiomyopathy, tachycardia,bradycardia, ventricular fibrillation, atrial fibrillation etc. Theheart sack of this invention can be reinforced with mono-filaments,yarns, braids, cords, knitted or woven or non-woven cloth made of abiocompatible, biostable, implantable polyamide, polyimide, polyester,polypropylene, and/or polyurethane etc.

The heart sack of this invention can be equipped with pacemaker leadsand defibrillation leads. The leads and electrodes of this invention aremade of noble metal or stainless steel deposited, coated or platedmono-filaments, yarns, braids, cords, wires, films, cloth and/orcylindrical tubes. The noble metal used for this invention is selectedfrom the group consisting of gold, platinum, rhodium and their alloys.The mono-filaments, yarns, braids, cords, wires, films, cloth orcylindrical tubes materials to be coated, deposited or plated with noblemetal are selected from the group consisting of poly(ethyleneterephthalate), poly(butylene terephthalate), polyamide, polyimide,polypropylene, polyetherurethane, polycarbonateurethane and theircopolymers. The heart sack and electrodes are very flexible and havegood biocompliance with heart muscle. They have high strength andexcellent mechanical properties. Ordinary pacemaker leads anddefibrillation leads could be also imbedded into the heart sack toprovide cardiac pacing or defibrillation.

REFERENCE

US4100309 Jul. 11, 1977 Micklus, et AL 427/002.28 US4515593 May 7, 1985Norton; William J 604/256 US4573481 Jun. 25, 1984 Bullara; Leo A 607/118US4612337 Sep. 16, 1986 Fox, Jr; Charles L 514/038 US4769013 Jun. 4,1986Lorenz et Al 604/265 US5242684 Sep. 7, 1991 Merianos; John J 424/078.07US5324322 Jun. 28, 1994 Grill, et Al 607/118

BACKGROUND OF THE INVENTION

Electrical therapeutic heart sack devices are a new and noble concept.Cardiomyopathy is a commonly observed disease in an aging population.Cardiomyopathy is a defect of myocardial function. There are threecategories of Cardiomyopathies; dilated cardiomyopathy, hypertrophiccardiomyopathy and restrictive cardiomyopathy. Dilated cardiomyopathyrefers to a condition in which there is weakened contraction of theventricles with an apparent dilation of the ventricles. This leads toinadequate perfusion, and increased pulmonary and systemic venouscongestion. It will lead essentially to loss of heart function. Thehistory of the disease is one of to progressive deterioration. Themortality in one year is greater than 50% for those people who have apoorly functioning heart. Hyper cardiomyopathy is a disease of the heartmuscle. It is characterized with an overactive left ventricle due to itsincrease in muscle mass resulting in an obstruction of the blood that isbeing pumped from the left ventricle to the rest of the body. Thiscauses dyspnea on exertion and chest pain due to ischemia. Currently,there is no treatment to alter the course of the disease. Restrictivecardiomyopathy is least common of cardiomyopathies. It is due to otherpathological processes such as scerderma, amyloid, sarcoid, or storagedecease. This invention is to prevent enlargement of the heart andthinning of the heart wall of patients with dilated cardiomyopathy, orhypertrophic cardiomyopathy by the use of a heart sack.

BRIEF SUMMARY OF THE INVENTION

The implantable heart sack of this invention was prepared from abiocompatible, biostable and implantable elastomer selected from thegroup consisting of polyetherurethane, polycarbonateurethane, silicone,polysiloxaneurethane and/or hydrogenated poly (styrene-butadiene)copolymer. Grooves can be made on the inside of the sack to accommodateblood vessels and pacing or defibrillation leads. Holes can be punchedout from the heart sack to accommodate the pulmonary artery and aorta.The heart sack can be made to be a semipermeable membrane by providingnumerous micro holes in the heart sack. This can be done mechanically,or by phase inversion casting method, or leaching out a soluble blendfrom an injection molded heart sack. Many larger holes can be perforatedin the heart sack to allow body fluid to freely flow around the heartsack. The heart sack of this invention can be reinforced withmono-filaments, yarns, braids, cords, knitted, woven and/or non-wovencloth made of a biostable, implantable polyamide, polyimide, polyester,polypropylene, or polyurethane etc. The heart sack is split from theupper edge of the sack through the pulmonary artery and aorta openings.In this way, the sack can be opened to fit onto the heart. Severalsutures are attached on one side or both sides of the cutting. Suturingmakes the heart sack fit tightly onto the heart. Ordinary pacemakerleads and defibrillation leads can bc imbedded into the heart sack totreat tachycardia, bradycardia, ventricular fibrillation atrialfibrillation etc. However, the ordinary pacemaker leads that interfacewith the exterior of the heart often lack physical and physiologicalcompliance with the heart to muscle and its surrounding tissue resultingin mechanical abrasion and scar formation. To prevent abrasion, thepacemaker leads and/or electrode of this invention are made of noblemetal or stainless steel coated, deposited or plated mono-filaments,yarns, braids, cords, wires, films, cloth cylindrical tubes, andlaminated films. These articles are encased in multi-lumen insulatingtubing having at least two lumens or in layers of the coaxial insulationtubes.

DETAILED DESCRIPTION OF THE INVENTION

When a man-made material is implanted in a human body, the bodyimmediately recognizes the presence of the foreign material. This willtrigger the immune defense system to eject or destroy the material andwill cause edema, inflammation of the surrounding tissue, andbiodegradation of the implanted material due to an enzymatic freeradical attack, hydrolysis, oxidation and environmental stress cracking.Only a few polymers are known to possess a long term biostability, andgood biocompatibility. The materials chosen for the implantable heartsack of this invention were selected from the group consisting ofpolyetherurethane, polycarbonateurethane, silicone, poly(siloxane)urethane, ethylene-propylene and dieyclopentadiene terpolymer, and/orhydrogenated poly (styrene-butadiene) copolymer. These polymers werechosen due to their elasticity, excellent biostability andbiocompatibility. The heart sack can be prepared from casting, coating,extruding, molding of these biocompatible and biostable materials. Thepreferred polyurethane is selected from the group consisting ofpoly(tetramethylene-ether glycol) urethanes andpoly(hexamethylenecrbonate-ethylenecarbonate glycol) urethanes such asDow Chemical Company Pellethane™ 90A, and Pellethane™ 55D. The preferredpolycarbonateurethane is Polymer Technology Inc Bionate™ or ThermedicsInc Carbothane™. The preferred silicone rubber has durometer hardnessrange of between 30 to 85. Both peroxide cure silicone and platinumcured silicone can be used. Examples are the Dow Corning Inc medicalgrade 70000 series, Q-4865 and Q-6860 series silicone, NuSil Inc MED4535, 4550, 4560, 4750, 4770, and 4780 series silicone, and equivalentproducts of other manufacturers. The preferred polysiloxaneurethane isElastomedics Elast-Eon™. The heart sack made from these polymerspossesses excellent long-term biostability, good biocompatibility, notoxicity and good resistance to the environmental stress cracking. Aheart sack can be reinforced with high strength fibers or filaments ofpolyamide, polyimide, polyester, and polypropylene or crosslinkedpolyurethane. The preferred reinforcing material is poly(ethyleneterephthalate), and poly(butylene terephthalate). The filaments andcords prepared from these polymer have very high tensile strength andhave good long-term biostability when imbedded in the aforementionedbiocompatible and biostable elastomers. Contoured grooves can be made onthe inside of the heart sack to accommodate blood vessels and pacing ordefibrillation leads by designing dies for the casting or molding. Theheart sack is split from the upper edge of the sack through thepulmonary artery, aorta and other blood vessel openings. In this way,the sack can be opened to fit onto the heart. Sutures are attached onone side or both sides of the cutting. Suturing enable to tie the heartsack tightly onto the heart.

The heart sack of this invention can be equipped with pacemaker leadsand defibrillation leads. However, care must be taken to preventmechanical abrasion of the heart muscle and surrounding tissues. Pacingand defibrillation leads of this invention comprises the noble metalcoated, deposited, or plated mono-filaments, yarns, braids, cords,wires, films, cloth or cylindrical tubes, and laminated films that areencased in multi-lumen insulating sleeves or coaxial tubes. The metalcoated, deposited or plated articles can be prepared by vacuum coating,vacuum deposition, chemical or physical deposition, spattering, chemicalor electric reductions of the metallic ions or chemical plating etc.Noble metals such as gold, iridium, platinum, rhodium and their alloysor corrosion resistant stainless steel can be coated, deposited orplated onto fibers and films to form an electric conductive electrodeand leads elements. Hereunder, these metal coated, deposited or platedproducts are referred as “noble metal coated” products.

To make the electrodes and leads, the noble metal coated mono-filaments,yarns, braids, cords, wires films, cloth or cylindrical tubes andlaminated films etc. must have excellent electric conductivity,biostability and biocompatibility. Noble metals, which meet theserequirements, due to their very low electric resistance, and excellentbiostability and biocompatibility, are gold, platinum, rhodium andplatinum-rhodium alloy. Preferred metals are platinum and platinumrhodium alloys. Platinum has an extremely low electric resistance of0.000275 ohm per meter. Biostability, to biocompatibility, and lowelectric resistance of platinum and platinum-rhodium alloys areextensively proven as the pacemaker and defibrillator electrodes.

The mono-filaments, yarns, braids, cords, wires, films, cloth orcylindrical tubes, and laminated films of this invention to be coated,deposited or plated with noble metal need to have high strength, goodbiocompatibility and long term biostability. Hereunder, thesemono-filaments, yarns, braids, cords, wires, films, cloth or cylindricaltubes, and laminated films may be referred as “fiber and film” products.Polymers, which meet these requirements, are poly(ethyleneterephthalate), poly(butylene terephthalate), polyamide, polyimide,polypropylene, polyurethane, and their copolymers. The preferredmaterial to make fiber, filament yarn and film is poly(ethyleneterephthalate) (PET). PET has an excellent physical strength, goodbiocompatibility, biostability, and is already utilized in constructionof artificial heart valves, and artificial blood vessels.

The highly electric conductive noble metal coated articles describedabove are encased in multi-lumen insulating tubing having at least twolumens or encased in coaxial tubing. The elastomers, which haveexcellent insulating properties and which meet requirements forimplantation are polyetherurethane, polycarbonateurethane, silicone,polysiloxaneurethane, polyfluoroethylene, or hydrogenatedpoly(styrene-butadiene) copolymer and the same as described in the aboveheart sack materials. Tubes made from these polymers are known to havean excellent long-term biostability, good biocompatibility, no toxicityand good resistance to the environmental stress cracking. It is knownthat hydrogen peroxide simulates the oxidative actions imposed by thebody against an implanted foreign material. The use of hydrogenperoxide, or hydrogen peroxide plus cobalt chloride to test biostabilityof materials is described in Journal of Biomaterials Research Vol. 29,467-475 and Journal of Biomedical Material Research Vol. 27, page327-334.

A multi-lumen tube of at least three lumens is preferred for the bipolarleads. The coaxial leads can be fabricated from alternating layers ofthe aforementioned insulating tubing and an electrically conductivematerial made of the noble metal coated mono-filaments, yarns, braids,cords, wires, films, cloth or cylindrical tubes. A special alloy MP35Ncoil also can be used as the leads electric conductor. The leads arefabricated in to such a way that one end of the leads or cable can beconnected to a pacemaker or defibrillator. The noble metal coated fibersand/or films protrude from another end of the multi-lumen leads orcoaxial leads for a designated length. They can be attached or bondedonto a narrow and thin strip of a insulating film, sheet or a slicedtube to form electrodes. The insulation material is made of one or moreof the aforementioned biocompatible, biostable and implantableinsulating polymer and has one or more grooves. The electrodes arebonded into grooves in parallel in a designated width, or the electrodeis attached individually on the separate insulation material. Multiplegrooves can be made to accommodate multiple electrodes. The insulationsheet that has grooves can be extruded using a film die with appropriateshape. To mount the noble metal coated fiber electrode into the groove,a round groove having the diameter slightly smaller to slightly largerthan that of the fiber with 1/32 to ½ of the circumference opened or cutaway is preferred. This enables the electrode to be retained in thegrooves and leaves 1/32 to ½ of the metal-coated fiber surface exposedon the surface of the insulating sheet. In the same manner rectangulargrooves can be made in an insulating sheet to accommodate the metalcoated film electrodes. The noble metal coated films can be laminatedwith one or more of the aforementioned biocompatible, biostable andimplantable elastomer sheet in parallel in a designated width from eachother, or individually bonded onto the separate insulation material tomake electrodes. The electrode and insulating ribbons can be heattreated and annealed to contour the heart sack. This assures tightcontact with the heart muscle. The pacemaker leads are fabricated insuch a way that one end of the leads can be connected to an implantedpacemaker or defibrillator. The noble metal coated electric conductiveelements protruded from another end of the leads can be also connectedto the regular pacemaker electrodes and defibrillator electrodes. Whenthe MP35N coil or silver /MP35N coil is used as electric conductivematerial for the leads, a portion of the protruding MP35N coil can beconnected to the ribbons or strips of metal coated fibers and bondedonto the insulation materials in the same manner described above. Theconnection area can be sealed with polyurethane, silicone or epoxy resinsealant to prevent short-circuiting and abrasion. The leads can beimbedded directly in the heart sack or inserted into the groove in theheart sack. The self-contouring and flexible electrodes provideexcellent to mechanical and physiological compliance to preventmechanically induced damages such as thickened epineurium, increasedsubperineural and endoneural connective tissue, endoneural edima,demmyelinization, or axonal degeneration. An ordinary pacemaker leadsand defibrillation leads can be also imbedded or inserted into thegroove in the heart sack to treat tachycardia, bradycardia, ventricularfibrillation, atrial fibrillation etc. Similarly the ribbons or stripsof the noble metal coated films that are laminated with theaforementioned implantable elastomer can be inserted or mounted ontoseparate areas of the inner side of the heart sack to provide for theproper pacing or defibrillation for the separate heart chamber. The filmelectrode, ribbon, fiber electrode and heart sack can be heated treatedto shrink or form a contoured configuration to fit exactly onto theheart, so that the electrodes make tight contact with the heart wall.

The whole heart sack can be made semipermeable or totally permeabledepending upon the hear sack size and physiological requirements. Thesemipermeable membrane can be prepared from a molding mixture ofpolymers with a designated molecular weight and proportion of leachingcomponent. Pore size and porosity is proportional to the molecularweight and amount of leaching compound. Leaching out the solublecomponent from an injection molded heart sack creates a semipermeablemembrane. A phase inversion casting method can be also used. Micro ormacro holes can be also mechanically perforated in the heart sack. Thiswill allow body fluid to freely flow around the heart sack. The numberand size of holes can be optimized depend upon the size of heart sackand physiological requirements.

It is desirable to eliminate the friction among the heart sack, leadsand heart muscle to prevent mechanically induced damage. The heart sackand noble metal coated leads materials have excellent biocompliance withthe heart muscle. Further reduction in the coefficient of friction canbe achieved by the use of a hydrophilic coating applied onto the leadsand electrode insulation surface. The whole heart sack and leadsassemblies, except the electrode surface, can be coated with a thinlayer of a biocompatible, hydrophilic coating to lower coefficient offriction. This type of coating was prepared from thepolyvinylpyrrolidone (PVP)-polyurethane interpenetrating polymer. Thecoating solution was prepared from dissolving polyvinylpyrrolidone andurethane into organic solvents. A hydrophilic coating also can be madeby depositing a solid polyvinylpyrrolidone derivative onto the heartsack. The PVP coating provides excellent biocompatibility and lowcoefficient of friction when wet with blood or body fluid. The coatingswells in water but will not dissolve or leach out and is extremelyhydrophilic.

An incidence of infection associated with the implantation of medicaldevices in the body is often life threatening. Some particularlypersistent infectious organisms are staphylococcus, staphylococcusepidermis, and pseudomonas auerignosa. Staphylococcus is especiallydangerous because it has an affinity for plastics. Enterooccus isanother gram-positive organism that causes life-threatening infectionand is resistant to a broad range of antibiotics. The incidence ofinfection associated with the implanted medical devices can be preventedwith the use of antimicrobial agents. Coating, impregnation andcompounding of antimicrobial agents on medical devices can preventinfection associated with the implant operation. Antimicrobial agents,which are suited for this purpose, are benzalkoniumchloride (BAC),chlorhexidine dihydrochloride (CHD), dodecarbonium chloride (DCC), andsilver sufadiazine (SSD). The amount of antimicrobial agent requireddepends upon the agent. It generally ranges from 0.0001% to 0.5%. BAC,DCC and SSD can be dissolved or dispersed in coating. Theseantimicrobial agents can be added to the biocompatible, lubricious andhydrophilic coating described in above. Anti microbial agents can alsobe added to a bioresorbable polymer solution of polyglycolide,polylactide or collagen. Medical devices can then be coated with thisantimicrobial solution. CHD due to its high decomposition temperatureand good thermal stability can be compounded into polyurethane andsilicone polymers and then extruded to form tubing, sheet and othershaped articles. These methods of antimicrobial coating, impregnation ofthe antimicrobial agents, or compounding of the antimicrobial agentsinto the insulation materials can be applied to any other type of heartsack, leads and electrodes.

EXAMPLE 1

A heart shaped polypropylene model including all blood vessel componentswas coated with a 10% solution of Pellethane 90AE inN-dimethylpyrrolidone and dried. The process was repeated three times toobtain an adequate coating thickness. Then, a screen made ofpoly(ethylene terephthalate) (PET) was placed onto the coated model andcoated again with the Pellethane solution. Coating and drying wererepeated several times. Then, the heart shaped skin was removed from themodel by making a slit from the center upper edge to below the aorta toobtain a heart shaped sack. Then, a number of polypropylene sutures wereattached on the both side of the slit. The sutures make it easier todose the slit and secure the heart sack on the heart.

EXAMPLE 2

A heart shaped polypropylene model including all blood vessel componentswas coated with a polyurethane solution prepared from polytetramethyleneether glycol having a molecular weight of 1,000, methylenebis-phenylisocyanate, and ethylenediamine in dimethylacetoamide anddried. The process was repeated two times to obtain an adequate coatingthickness. Then, a screen made of poly(ethylene terephthalate) (PET) wasplaced onto the coated model and coated again with the Pellethanesolution. Coating and drying were repeated several times. Then, theheart shaped skin was removed from the model by making a slit from thecenter upper edge to below the aorta to obtain a heart shaped sack.Then, a number of polypropylene sutures were attached on the both sideof the slit. The sutures make it easier to dose the slit and secure theheart sack on the heart.

EXAMPLE 3

To the Pellethane solution of example 1, two percent of polyethyleneglycol having molecular weight of 1000 was dispersed. Then, the solutionwas applied to the polypropylene heart model in the same manner. Thecoating was dried and annealed. Thus obtained heart sack was placed in60° C. water bath for 60 minutes to leach out the polyethylene glycol.After drying a heart sack with a semipermeable membrane was obtained.

EXAMPLE 4

Poly(ethylene terephthalate) monofilament having a 20 micron diameterwas plated with approximately 0.5 micron thick platinum. A yarnconsisting of 48 platinum deposited monofilament was braided to make anelectrically conductive wire. The braid having a 60 mm length and 1.8 mmdiameter had an electric resistance of 0.7 ohms. A platinum coated fiberbraid 800 mm long and 0.6 mm in diameter had a tresistance of 35 ohms.The product had extremely good corrosion resistance. No corrosion wasfound after 400×15 amp 0.10 milli-second defibrillation shocks in 0.9%saline. The platinum-coated fiber had very low toxicity and passed boththe ASTM F813 Cytotoxicity Assay and the Cell GrowthInhibition-Cytotoxicity Assay.

EXAMPLE 5

Two braids of platinum deposited poly(ethylene terephthalate) fibershaving 0.6 mm dia were inserted into two lumen Pellethane tubing. Thebraids protruding from one end of the tubing were connected to theadapters that fit into a pacemaker. The braids protruding from the otherend of the tube were bonded into a groove in the inner surface of theheart sack in such way that the electrodes are exposed on the innersurface of the heart sack. Then the heart sack was placed on thepolypropylene heart model and annealed at 85° C. for two hours. Aftercooling hear sack equipped with the electrode and leads contoured withthe heart sack was obtained.

EXAMPLE 6

MP 35N coils were placed in tubing (2.4 mm dia, 0.2 mm wall thickness)made of Pellethane 55D, Pellethane 80A, and peroxide cured silicone.Then, the tubing was bent in a U-shape and placed separately in 1-indiameter test tubes containing 10% peroxide solution. A braid made ofplatinum coated PET was also bent in the same u-shape and placed in atest tube containing 10% peroxide solution. Pellethane 55D which ismanufactured by Dow Chemical and which is known as a biostable andbiocompatible polyurethane and Pellethane 80A which is known to besusceptible to the environmental stress cracking under mechanical stresswere used as positive and negative controls. Test tubes were covered bywaxed plastic film and placed in an incubator at 37° C. After 6 weeks ofincubation, the tubes and braids were examined under microscope.Micro-cracks were observed in the bent area of the Pellethane 80A tube.No cracks or fissures were observed on either the Pellethane SSD or thesilicone and platinum coated PET.

EXAMPLE 7

Polytetramethylene ether urethane (PEU) was prepared from methylenediphenyl isocyanate (MDI), poly(tetramethylene ether) glycol (PEU), andbutanediol. Films (2 mm×10 mm×0.5 mm) were extruded from the PEU. Thesame size films were also extruded from polycarbonateurethane (PCU)prepared from MDI and poly(hexamethylene carbonate-ethylene carbonate)glycol (PCU), and poly(ethylene terephthalate) (PET). Platinum coatedpoly(ethylene terephthalate) (Pt-PET) film, and PET film coated withpolyvinylpyrrolidone interpolymer (Pt-PVP) were also obtained. All filmswere placed in separate vials and exposed to fresh platelet plasmaconcentrate. The vials were incubated at 37° C. for 30 minutes withslight agitation. Then, the films were rinsed in cold phosphate bufferand treated with 3% glutaraldehyde, dehydrated serially with increasingconcentration of ethanol and air dried. Thus obtained samples werespatter coated with gold and examined using scanning electronmicroscope. The amounts of platelet adhesion and degree of plateletactivation were measured. Round platelet and no pseudopodia present wasrated 1, a few pseudopodia with no flattening was rated 2, one or morepseudopodia flattened and hyaloplasm not spread between pseudopodia wasrated 3, hyaloplasm partially spread was rated 4 and hyaloplasmextensively spread were rated 5. Thus, the smaller the number the betterthe biocompatibility. The ratings obtained were: PEU 2, PET 4, PCU 3,Pt-PET 2, and Pt-PVP 1.

EXAMPLE 8

A semipermeable heart sack was obtained by coating and drying a heartshaped model with appropriate blood vessel features and have holes andgrooves for the pacemaker leads or defibirillation leads or both, with amixture of polyethylene glycol (PEG) having 600 molecular weight withthe elastomer solution prepared from the reaction of polytetramethyleneether glycol having a molecular weight of 1,000 and methylenebis(p-phenylisocyanate) with the molar ratio of 1 to 1.6 to 1.9respectively in N,N′dimethylacetoamide (DMA) at 85° C., then adding amixture of ethylene diamine, 1,3 diaminocyclohexane and diethylamine inDMA (1:0.24:0.19 molar ratio respectively) to chain extend to obtaineapproximately 30% solution, and adding 0.025% each of 4,4′buttylidene-bis (6-t-butyl m-cresol) and 2 diethyaminoethymethacrylate-n-decyl methacrylate copolymer as stabilizer. After asufficient thickness is obtained by the repeated coating and dryingprocesses, the product was placed in a 45° C. water bath to leach outthe water soluble PEG. The porosity and pour size of the products werecontrolled by the molecular weight, amount of PEG and leachingtemperature. Thus obtained heart sacks were removed from the mold makingslits. Then, polypropylene sutures with needle were attached on bothside of the slits. The suture enabled to secure the heart sack on theheart model and demonstrated convenience of the built-in suture.

EXAMPLE 9

The inner and outer surfaces of polyurethane heart sacks of example 8were coated with a PVP urethane interpolymer solution. The coatingsolution was prepared dissolving 1.5 percent weight PVP having 30 Kvalue that is related to molecular weight of PVP, 0.5 percent weight ofan adduct of methylene bis-cyclohexyl isocyanate and poly(tetraethyleneether) glycol having 1000 molecular weight, 0.3% isocyanate terminatedcaster oil and 0.005% stannous octoate catalyst in the mixture ofsolvents consisting of 35% methyl ethyl ketone, 20% ethyl lactate, 10%ethyl acetate, and 35% trichloroethylene. The coating was dried in anoven at 50° C. for 2 hours. A coated test sheet of polyurethane sheetprepared in the same manner demonstrated a high degree of lubricity whenwet and had about one quarter the friction of Teflon.

EXAMPLE 10

A piece of polyvinylpyrrolidone-urethane coated heart sack material (2cm diameter) was immersed in saline solutions containing 0.1%benzalkoniumchloride (BAC) and then dried. The pierce was placed on aculture dish containing staphylococcus epidermis and incubated at 37° C.for 3 days. A more than 5 mm of zone of inhibition was observed in theculture dish. Similarly, the polyvinylpyrrolidone-urethane coatedelectrodes immersed in saline solutions containing 0.1% of chlorhexidinedihydrochloride (CHD) and dodecarbonium chloride (DCC) showed more than5 mm of zone of inhibition.

1-20. (canceled)
 21. An apparatus for treating cardiomyopathy of a heartcharacterized in part by dilation of ventricles of the heart, theapparatus comprising: a device configured to completely surround atleast the ventricles of a heart, said device including: a materialconstructed of a biocompatible material and shaped and sized tocircumferentially surround the heart and covering at least theventricles of the heart in contact with opposing tissue of said heart;and a plurality of electrodes carried on said device and positioned toelectrically contact a surface of the heart when said device ispositioned on said heart with said material surrounding said ventricles;and said electrodes adapted to be electrically connected to anelectrical impulse generator.
 22. An apparatus according to claim 43further comprising an implantable electrical impulse generator operablyconnected to the electrodes, said impulse generator adapted to generatean electrical signal to be imparted to said heart through saidelectrodes.
 23. An apparatus according to claim 43 wherein said materialcarries a pharmacologic agent.
 24. An apparatus according to claim 43wherein said material is at least partially coated with surface coating.25. An apparatus according to claim 44 wherein said signal is a pacingsignal.
 26. An apparatus according to claim 44 wherein said signal is adefibrillation signal.
 27. An apparatus according to claim 43 whereinsaid material is shaped and sized to cover an atrium of the heart. 28.An apparatus according to claim 43 wherein said material includes aplurality of holes through said material.
 29. A cardiac reinforcementdevice, said device comprising: a sack of biomedical material configuredto completely surround at least the ventricles of a heart and preventcardiac expansion, said sack comprising a open base end for applyingsaid sack to the heart such that when applied the base end is orientedtoward the base of the heart and said material surrounds and contactssaid ventricles; and a plurality of stimulation electrodes configured tocontact the heart, whereby the sack is configured to resist dilation ofthe heart and the stimulation electrodes are capable of improvingcardiac contraction.
 30. A method for treating a disease of a heart, themethod comprising: selecting a device adapted to be placed against asurface of the heart, the device comprising a material sized andconfigured to surround at least the ventricles of the heart and aplurality of stimulation electrodes configured to contact the heart;surgically placing said device on said heart with said materialcontacting a surface of said heart at least surrounding said ventriclesand with said material circumferentially surrounding said ventricles,said placement including positioning said device with said electrodeselectrically contacting said heart; applying a therapeutic electricalsignal to said electrodes.
 31. A method according to claim 50 whereinsaid device is sized and configured to cover an atrium of said heart.32. A method according to claim 50 wherein said therapeutic electricalsignal is a pacing signal.
 33. A method according to claim 50 whereinsaid therapeutic electrical signal is a defibrillation signal.